Description of the Process of Manufacturing Coal Gas, for the Lighting of Streets Houses, and Public Buildings / With Elevations, Sections, and Plans of the Most Improved Sorts of Apparatus Now Employed at the Gas Works in London and the Principal Provincial Towns of Great Britain; Accompanied With Comparative Estimates, Exhibiting the Most Economical Mode of Procuring This Species of Light

by Friedrich Christian Accum

To find the capacity of a revolving gas holder, of given dimensions, take the area of the whole diameter, then the area of the inner cylinder, multiply the difference by the length, and from this deduct one-fourth.

Collapsing Gas Holder.

The collapsing gas holder is a still farther improvement by Mr. Clegg, on this part of the gas light apparatus, and certainly of all the contrivances which have been invented for collecting and storing up large quantities of gas, this machine must be pronounced to be by far the most simple, economical, and efficient. The striking advantage of the revolving gas holder which we have just been describing is, that it enables the dimensions of the tank to be very much diminished, where the nature of the ground will not admit of a cistern of great depth being sunk, except at an extraordinary expence; but the still superior feature of the collapsing gas holder which we now come to describe, is, that it may be constructed of any required capacity, and adapted to a tank or cistern of such diminished depth, as scarcely to deserve that name. It requires a sheet of water no more than 18 inches in height, so that it may be constructed in or upon ground of all descriptions, not only with every possible facility, but at an immense saving of expence.

Fig. 1, [plate VII.], exhibits a perspective view of this gas holder. It is composed of[43] two quadrangular side plates joined to two end plates, meeting together at top in a ridge, like the roof of a house. The side and end plates are united together by air tight hinges, and the joints are covered with leather, to allow the side plates to fold together and to open in the manner of a portfolio. The bottom edges of the gas holder are immersed in a shallow cistern of water, to confine the gas. By the opening out or closing up of the sides and ends of the gas holder, its internal capacity is enlarged or diminished, and this variation of capacity is effected without a deep tank of water to immerse the whole gas holder in, as required in the ordinary construction of rising and falling gas holders. The collapsing gas holder requires therefore only a very shallow trough of water to immerse the bottom edges of the gas holder to prevent the escape of the gas introduced into it. The lower edges of the gas holder which dip in water are made to move in an horizontal plane or nearly so, when they are opened, so that they dip very little deeper in the water when shut or folded together, than when opened out.

[43] From Mr. Clegg’s specification—the same letters of reference indicate the same parts in all the designs.

For this purpose the top or ridge joints which unite the two sides of the gas holder, are slightly raised up when the sides close or approach together, or slightly depressed when the sides open out or recede from each other. To guide the whole gas holder in this movement, two perpendicular rods rise from the bottom of the shallow tank which pass through sockets in the ridge joints at the upper part of the gas holder. These sockets are secured by collars of leather round the shafts or rods, to prevent the escape of the gas, and they are braced by chains proceeding from their upper extremities and fastened at the ground on each side of the tank.

The weight of the gas holder is balanced by levers bent in the form of the letter L, and placed inside of the gas holder. These levers move on centre pins fixed at the bottom of the shallow trough, which pass through the angles of the L levers. The perpendicular arms of the levers are jointed at their upper extremities to the sides of the gas holder, nearly in the middle. At the ends of the horizontal arms of the L levers, are weights to counterbalance the weights of the gas holder, and both sides of the gasholder are provided with these kind of levers, which at the same time that they balance its weight cause the ridge joint of the machine to rise and fall, as before described, so that the under edges of the gasholder, which are immersed in the water to confine the gas, must move in an horizontal plane instead of describing an arc of a circle as they would do if the ridge joint was a fixed centre of motion.

When the gas holder is closed the perpendicular arms of the levers stand nearly in a perpendicular position, but when the gas holder is opened out the levers become inclined. And as they move upon a fixed fulcrum at their lower extremities, and are jointed to the sides of the gas holder at their upper extremities, they allow the whole of the gas holder to descend gradually upon the guide rods, nearly in the same degree as the lower edges would rise up if the ridge joint was stable, and if the sides described an arc of a circle.

It is obvious, however, that the latter movement is not very essential, but it is convenient and necessary to make a very inconsiderable depth of water in the trough or tank serve the purpose it is intended. It may be also observed that the sides of the collapsing gas holder may be made to unfold or open on a fixed ridge point as a centre of motion, but it will then require a considerable depth of water in the tank to keep the lower edges of the sides and ends of the machine always beneath the surface of the water, because the sides of the gas holder then describe an arc of a circle when they are open. Fig. 1, [plate VII.], is a perspective view of the apparatus, as it appears when partly filled with gas. Fig. 2, [plate VI.], exhibits a perpendicular longitudinal section made through the middle of the gas holder and tank; fig. 3, [plate VI.], represents a transverse section; fig. 4, [plate VI.], is an end view of the machine, and fig. 5, exhibits an horizontal plan or section of part of the gas holder, or one of its ends, to show how the end plates are jointed together, and the leather applied to prevent the escape of the gas.

A, fig. 2, is the inlet pipe which conveys the gas into the machine, it rises up perpendicularly through the water in the tank, high enough to prevent the water entering it. B, is the exit pipe for discharging the gas into the mains from the gas holder. It rises up nearly to the top of the machine. C, C, are the guide rods, they are firmly fixed at their lower extremities into a cast-iron framing D, D, beneath the bottom of the tank. The upper ends of these rods are kept steady by chains E, E, fig. 3, and fig. 4, descending on each side of the gas holder, and fastened at bottom to D, D, part of the same iron framing. F, G, K, K, are the balance (or L) levers which suspend or bear up the gas holders; they move on fixed centre pins supported in pieces a, a, fig. 2, and 3, of the framing D. The upper end of the perpendicular arms are jointed to the iron bars H, H, H, see fig. 2, which are riveted to the side plates of the gas holder; they are united by knuckle joints W, fig. 6, which allow the sides of the machine to approach each other till they come together. The arms i, i, of the bent levers F, G, K, K, fig. 4, are placed nearly at right angles to the other arms F, G, fig. 3, and the extremities of the arms i, i, are loaded with counterpoise weights K, K, which always tend to bring the arms F, G, into a vertical position, and consequently to close up the sides of the gas holder, in order to expel the gas through the exit pipe B, fig. 2.